More than 680 large fish have been relocated in a week for a $427 million dam upgrade.
Ecologists shifted multiple species to accommodate the Lake Macdonald Dam Improvement Project near Noosa.
Australian bass, eel-tailed catfish and longfin eels were among the animals to be transferred as the dam is upgraded to meet modern engineering and design standards.
An impressive Mary River cod – listed as endangered – was also moved.
An Seqwater spokesperson detailed how the mass relocation occurred.
“A combination of electrofishing, fyke netting, sonar and habitat assessments were used to safely and effectively identify and relocate the fish (to Cooloolabin Dam),” they said.
“Expert fish ecologists used a purpose-built transport vehicle to relocate them.
“The one large-bodied Mary River cod (93cm, 7kg) that was caught had genetic samples taken and the fish was measured, weighed and tagged prior to release in the Mary River.”
Ecologists said it’s highly likely that the finding of this fish was the result of previous stocking activities and it had grown to a large size in the lake.
The spokesperson said scientists would track water quality at Lake Macdonald and Cooloolabin Dam “to assess relocation success and long-term ecological outcomes”.
The spokesperson detailed why the fish required relocating.
“Lake Macdonald Dam is being upgraded to meet modern engineering and design standards, ensuring ongoing safety in extreme weather events and providing water security for generations to come,” they said.
“The temporary cofferdam keeps most of the water in the lake but some lowering is needed to safely undertake construction works.
“The fish salvage and relocation reduces impacts on aquatic species during the lake drawdown and construction phases.”
The spokesperson said turtles and small-bodied fish were not shifted because ecology experts determined they were suited to adapt to changing lake conditions.
“Environmental monitoring will continue, guided by an adaptive management plan,” they said.
The dam upgrade is expected to take five years.
“Post-construction, the lake will naturally refill, be restocked with fingerlings and enhanced with habitat logs and root balls,” the spokesperson said.
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A project update was recently issued by Seqwater with information about construction, which was started by building company John Holland.
Phase 1 includes lowering the lake and building the temporary cofferdam.
“Seqwater is conducting continuous environmental monitoring throughout the project and maintaining environmental flows to support downstream habitats,” the spokesperson said.
The Mary River Cod Park and boat ramp are closed, along with the fishing platform on Lake Macdonald Drive. However, recreation activities at Lake Macdonald, Lake Macdonald Park and boat ramp, and the Noosa Botanic Gardens remain open.
The Elm Street and Lake Maconald Drive intersection will be upgraded from mid-September until November. Heavy vehicles will continue to use those two roads during the project.
